Proc glm

[Dylans15]

Hello,

I am conducting an ANOVA using proc glm and was wondering about confidence interval.

I do not mention CI in my code. Does that mean that it assumes 95%, or is another statement needed?

proc glm data=sasdata.ptsd;
class PTSD;
model auditscore=PTSD;
means PTSD;
run;
quit;

Thanks

[Reeza · Accepted solution]

The default alpha is 5% so 95% confidence intervals. 

You can modify the defaults. 

Be careful with default settings, they do things you don't expect sometimes, a CLASS statement being the most problematic usually. For example, check your design matrix and ensure the coding is what you wanted.

model auditscore=PTSD / alpha=0.05;

Or

proc glm data=sasdata.ptsd alpha=0.05;

From the docs:

https://documentation.sas.com/?docsetId=statug&docsetTarget=statug_glm_syntax01.htm&docsetVersion=14...

ALPHA=p

specifies the level of significance p for % confidence intervals. The value must be between 0 and 1; the default value of p = 0.05 results in 95% intervals. This value is used as the default confidence level for limits computed by the following options.

Statement	Options
LSMEANS	CL
MEANS	CLM CLDIFF
MODEL	CLI CLM CLPARM
OUTPUT	UCL= LCL= UCLM= LCLM=

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@Dylans15 wrote:

Hello,

I am conducting an ANOVA using proc glm and was wondering about confidence interval.

I do not mention CI in my code. Does that mean that it assumes 95%, or is another statement needed?

proc glm data=sasdata.ptsd;
class PTSD;
model auditscore=PTSD;
means PTSD;
run;
quit;

Thanks

---

[Dylans15]

Thank you!